package com.ouc.dcrms.core.util;

import java.security.MessageDigest;

/**
 * @author WuPing
 * @version 2017年2月19日 下午4:43:04
 */

public class CheckSumBuilder {
    // 计算并获取CheckSum
    public static String getCheckSum(String secret, String nonce,
	    String curTime) {
	return encode("sha1", secret + nonce + curTime);
    }

    // 计算并获取md5值
    public static String getMD5(String str) {
	return encode("md5", str);
    }

    private static String encode(String algorithm, String value) {
	if (value == null) {
	    return null;
	}
	try {
	    MessageDigest messageDigest = MessageDigest.getInstance(algorithm);
	    messageDigest.update(value.getBytes());
	    return getFormattedText(messageDigest.digest());
	} catch (Exception e) {
	    throw new RuntimeException(e);
	}
    }

    private static String getFormattedText(byte[] bytes) {
	int len = bytes.length;
	StringBuilder buf = new StringBuilder(len * 2);
	for (int j = 0; j < len; j++) {
	    buf.append(HEX_DIGITS[(bytes[j] >> 4) & 0x0f]);
	    buf.append(HEX_DIGITS[bytes[j] & 0x0f]);
	}
	return buf.toString();
    }

    private static final char[] HEX_DIGITS = { '0', '1', '2', '3', '4', '5',
	    '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
}
